Ballistic gelatin test results : 5.45x39mm Wolf HP

[Brass Fetcher]

Special thanks to rbernie, who sponsored this test in full.

Cartridge : 5.45x39mm 60gr Wolf hollowpoint

Firearm : Romanian AK74 with 16.0" barrel length

Block calibration : 10.3cm @ 584 ft/sec (depths corrected up to point of bullet yawing)

Single shot fired to the center of 10x10x16" ballistic gelatin block. Shot was fired at 10' distance and impacted at 2871 ft/sec. Bullet traveled point-forward to 8.4" (with slight yawing beginning at 3.4" depth). At this point, the bullet turned approximately 90 degrees with respect to its initial line of travel, producing cracks in the gelatin of 3.9" maximum diameter. The bullet experienced minor fragmentation at this point, sending a fragment weighing 3.9gr at a ~45 degree angle for 2.1" (uncorrected) depth and a second fragment of 2.1gr to a 1.3" (uncorrected) penetration. At ~8.6" depth, the bullet veered left of its initial direction of travel at a 40 degree angle. At the rear face of the block, a rectangular hole measuring 1.9" wide by 0.20" high was noted, as well as a golf-ball sized piece of gelatin on the verge of separation from the back of the block.

The polyester bullet arresting material was contained in a black plastic trash bag and placed 1" rearward of the gelatin block. Three slivers of black plastic bag were drawn ~ 3" into the wound channel by the passage of the bullet into the plastic bag. The bullet was recovered at an unknown distance into the polyester bullet arresting box.

Side of the block with calibration BB:

Rear face of the block:

Piece of gelatin nearly pushed out by the bullet:

 

[rbernie]

Thanks for doin' all this....

 

[Lucky]

So in your opinion does the HP perform worse than the Steel Core?

 

[Geronimo45]

That's quite a performance. Thanks for your work - as always, a job well done.
How's that round compare to 5.56?

 

[JShirley]

Thank you. Sound like a lot of penetration!

Any plans to do the 5.45mm 70 grain?

How would one contribute to your efforts?

John

 

[sefus]

I heart 5.45x39!

 

[JShirley]

I recently bought one for my SO's upcoming birthday. She used to shoot smallbore competition in high school, but hasn't shot many centerfire rifles. I wanted a rifle that would have very little recoil, so she would enjoy shooting it- enjoying shooting it, would shoot it more often- shooting it often, would become good with it.

And that was more important than a rifle that hit like the hammer of Thor. But I'd still like to know the most effective choices.

 

[rbernie]

I was hoping that the Wolf 60gr HP would display some significant fragmentation, leaving the Wolf 70gr stuf to act as the 'penetrator' rounds. Sadly, the neck on the wound channel is far longer than I'd have liked and the wound channel doesn't start to get interesting until almost 9" into the block. That's really too deep for social work against open targets. It may work well as a GP round where penetration of intermediate barriers is important, but it's probably not my first choice for repelling boarders.

 

[Brass Fetcher]

@JShirley - I've got a 'donate' icon on the front page of www.brassfetcher.com. That is how most people do it (and it is all greatly appreciated). That is an interesting choice of rifle for your application... the 5.45x39mm is fast becoming one of my favorite EBR-type cartridges. Yes, I can fit in the 70gr cartridge test in the near future.

Yeah, I was slightly disappointed that the bullet didn't yaw earlier. FWIW, the 'slight yawing' that took place created a permanent cavity similar in size to a .40S&W FMJ. I'm thinking that the results would be a lot more favorable with a 'fast-shooting' AK74 (I'm sure the barrel on the one I was using had seen better days) or the longer-barrel 5.45mms... With greater velocity, the imbalanced drag force of the gelatin on the bullet should be significantly higher, causing tumbling earlier.

 

[rbernie]

With greater velocity, the imbalanced drag force of the gelatin on the bullet should be significantly higher, causing tumbling earlier.

I'm thinkin' that the 70gr will display less yaw than the 60gr which displayed less yaw than the 53gr. I can only guess that the lightweight 53gr 5.45 projectile is significantly more rear-heavy than the heavier bullets, which will cause it to tumble earlier than the heavier 60gr or 70gr bullets....

It's too bad that the Russians don't make/import a SP sporting round for this chambering....

 

[Brass Fetcher]

I found the bullet...

Here is what the bullet looked like :

 

[rbernie]

So it *did* fragment - it just took twelve inches of penetration into the ballistic gelatin to do it.

Thanks again for the test....

 

[JShirley]

rbernie:

I would think the longer bullet would be more likely to tumble.

 

[rbernie]

As I understand things, it's weight imbalance that makes things tumble, not length. Length *may* imply fragmentation upon tumbling, but if the bullet is pretty stoutly constructed it may not fragment no matter how long it is. The only time length helps is if (as appears to be the case with the 53gr milsurp) the long length implies a bigger air pocket up front and therefore a more tail-heavy design.

If the 70gr has a really big air pocket up front, it may tumble quickly. However, I'm thinkin' that it probably tries to squeeze more weight into a similar bullet OAL as the 53gr/60gr designs. That would imply that the 70gr is actually a better balanced bullet than the 53gr, not a less balanced bullet.

I suspect that the 53gr bullet tumbled much more dramatically than the 60gr because it has a bigger air pocket up front as a function of having less lead poured into a space of equal OAL and diameter.

 

[Brass Fetcher]

A handy way to look at this would be to think of a see-saw at a playground... take a heavier kid, put them at the other end and they are harder to lift off the ground than a lighter kid. Ask them to move closer to the axis of rotation and they can be lifted faster - it's a matter of 'moment' which is a function of weight and distance from the center of rotation.

This idea is the same for tumbling bullets - in free flight through the gelatin, the axis of rotation is the center of mass of the bullet. So, the bullets with the weight intentionally distributed more towards the back (IE those bullets with airspaces at the tip) are going to rotate about an imaginary line or axis more towards the back of the bullet (where the lead is). This leaves more of the jacket length to act as a lever arm (like the wood plank you sit on on a see-saw), to rotate the bullet in the presence of any 'imbalanced force' from the drag of the gelatin or water. Hence, the longer a bullet is and and more weight concentrated at the base of the bullet, the more likely it is to tumble earlier in the penetration track.

 

[Dr.Rob]

Ouch! That's one wicked looking result.

 

[repo]

I just saw the price of 5.45 ammo, I need to get one of these rifles.

 

[possum]

thanks again, much appreciated.